The present invention relates to local access network architectures and, more particularly, for supporting competition among local exchange carriers.
FIG. 1 is an abstract diagram of the current local access architecture for telephony and other local services such as ISDN or digital subscriber line service. In FIG. 1, a plurality of telephony subscribers at customer premises 116, 117, 118, 126, 127, 128, 136, 137, 138 in customer serving areas (CSA) 101, 102, 103 are provided with local exchange service by an incumbent local exchange carrier (ILEC). The ILEC maintains a plurality of local serving offices (LSO) 110, 120, 130 which connects to the customer premises in basically three known ways: (1) using conventional copper wires 135 connected directly to a switch 133 in the central office 130 via a serving area interface (SAI) 134; (2) using a legacy universal digital loop carrier (UDLC) system to multiplex encoded digital channels of the customer signals from a remote terminal (RT) 123 to a central office terminal (COT) 122 next to the switch 121 in the central office (120) via a SAI 124; or (3) using the more advanced integrated digital loop carrier (IDLC) 113 system to multiplex customer signals to the switch 111 in the central office 110 via a SAI 114. These digital loop carrier systems improve the economics of loop development by using telephone line cards at each remote terminal that convert the analog signal from a copper loop into 64 kb/s encoded digital signals. The digital channels are multiplexed, using time division multiplexing (TDM), on an optical transport (e.g. OC-1, OC-3 SONET) between the remote terminal and the central office, in accordance with Telcordia GR-008 125 or GR-303 115 interface standards. The central offices 110, 120, 130 also typically connect to each other using optical links—as well as with the rest of the ILEC network 100.
Federal legislation and regulations have recently mandated that ILECs provide other entities, referred to as competitive local exchange carriers (CLECs), with “unbundled” access to the local access infrastructure in order to provide competitive local services. Where a CLEC desires to connect to the unbundled local loop of a subscriber, this presents numerous challenges, as illustrated in FIG. 1A. Where the subscriber loop 135 is directly connected to the LSO switch 133, this necessitates what is referred to in the art as a “coordinated hot cut”, represented as a box 132 labeled XC. The copper wire pair is manually transferred by a technician, at the Metallic Distribution frame and re-routed from the central office switch 133 and connected to equipment, e.g. 153, 163, co-located by the CLEC 150, 160 at the central office 130. Each CLEC 150, 160 must co-locate their own equipment at each central office 110, 120, 130 in order to provide local services to each unbundled local subscriber in the respective customer serving areas 101, 102, 103. This transfer of the subscriber loop is coordinated with a request, through the Local Number Portability process, to port the subscriber's telephone number to the CLEC's Class 5 switch. Moreover, if a customer desires to switch local exchange carriers, this requires another expensive manual “hot cut” transferring the copper loop to another LEC's equipment at the central office. The current digital loop transmission systems further complicate this expensive, time-consuming and error-prone process, requiring specialized interfaces to ILEC central office equipment.
Accordingly, there is a need to provide a local access architecture that reduces the costs of provisioning local services for subscribers and permits competitive local exchange carrier services without requiring manual local loop transfers.